The continued production of functional blood cells is based on maturation of multipotent progenitors gradually loosing lineage potentials to end up as progenitor cells committed into a defined category of blood cells. This process involves an intricate interplay between transcription factor networks acting to drive development by activation of transcriptional programs but also to impose epigenetic silencing of genes associated with alternative blood cell types to ensure stable lineage commitment. The maturation process is further under the influence of external regulatory cues provided by the microenvironment in the bone marrow. Our laboratory focuses the research on understanding the molecular processes that regulate B-lymphocyte differentiation and lineage commitment as well as the disruption of these networks underlying malignant transformation in leukemia (B-ALL) - one of the most common causes of childhood malignancies.